New method recycles lithium-iron-phosphate batteries cheaply

Carmakers are quickly adopting the newest generation of rechargeable lithium-ion batteries, which are cheaper than their predecessors. But recycling lithium from the lithium-iron-phosphate (LFP) cathodes in these cells may not be economically viable using existing methods. A team of researchers says its new electrochemical approach could be a solution (ACS Energy Letters, 2025, DOI: 10.1021/acsenergylett.5c01087).

“It’s a conceptually novel approach to LFP recycling and a real advance in electrochemical separation science,” Volker Presser, an energy materials scientist at the Leibniz Institute for New Materials and Saarland University, tells C&EN in an email. Presser was not involved in the new study.

Most electric vehicles in the US and Europe use battery cathode materials that contain cobalt, nickel, and manganese. The energy- and material-intensive processes used to recycle these batteries, such as melting them down or leaching materials out, are profitable because of the value of the metals, according to Kyoung-Shin Choi of the University of Wisconsin–Madison, who developed the new recycling method with her research group.

But market projections suggest that cheaper LFP batteries will outnumber those batteries in the next decade, with consequences for recycling. “Unless you come up with a completely different way to recover lithium, recycling LFP batteries is not viable,” Choi says.

Adapting its previous work using electricity to extract and recover ions from water, Choi’s team developed a water-based process to extract pure lithium and other species from spent cathodes. Using phosphoric acid and hydrogen peroxide, the researchers first extracted lithium and phosphate ions from the cathode material or from a ground-up mixture of battery materials called black mass, which is the starting point for most recycling.

They then put this solution into an electrochemical cell, where the ions were extracted by electrodes. The electrodes were moved to a second cell, where the ions were released back into a solution, and finally precipitated as lithium phosphate. The lithium phosphate can be used to make new cathodes. Also, depending on the electrode materials setup chosen by the researchers, the process can regenerate the phosphoric acid used in the first step or make other products. Presser points out that the process uses little energy: roughly 1 kW·h to make 1 kg of lithium phosphate.

Key to the recovery system is the lithium titanium phosphate in the system’s storage electrode. The material’s orthorhombic crystal structure seems to enhance its durability, as lithium ions go in and out during the recycling process.

The researchers are now working on scaling up their system to explore commercializing the technology, which they have patented. Choi acknowledges they have a ways to go. Presser echos that, saying the new process’s future may largely hinge on the costs of developing industrial-scale infrastructure and on as-yet-unanswered questions about its performance at scale.